The overall motivation behind my research is to understand how the brain works, and I have chosen to focus on neuro-computational modeling of the cognitive processes and neural mechanisms involved in speech and language. My current work investigates processes underlying speech production and perception. In particular, I am exploring learning and representation in speech. The theoretical foundation for this investigation is, in part, the DIVA model (Guenther, Ghosh and Tourville, 2006). This model provides a number of hypotheses and predictions related to what (representations), when (time course of processing), and where (brain regions involved) changes related to learning take place. In my doctoral dissertation work, I extended the DIVA model to address learning and motor control in the presence of sensory feedback and cortico-cortical transmission delays.

Combining theoretically based neuro-computational modeling with hypothesis-driven experimental work provides a synergistic approach to understanding brain mechanisms. I use a combination of fMRI and psychophysical experiments on adult populations with and without neurological disorders, whose results supplement the model. My experiments involve perturbation and adaptation paradigms that alter sensory feedback in realtime. The results show that the brain monitors mismatches between sensory feedback and expected sensory consequences. In addition, the results demonstrate that the motor system adapts its output to compensate for the mismatch.